Variable-stroke hydraulic pump



. c. L. BolssEr. VARIABLE STROKE HYDRAULIC PUMP..

l APPLICATION miams. 1o, |921., v v 1,418,616, f Patented June 6,1922.

@SHEETS-SHEET l.

Z0 v I '54 Afro/mers c. L. olssfr.

VARIABLE STRQKE HYDRAULIC PUMP.

APPLICATION `FILED HEB. I0. 1.921. 'l Patented June 6 3 SHEETS-SHEET 2.

INVENTOR CH/v1/fLE54.B9/ss7;

I L CHA Rbge; B0/@Jv- Qg? C. L. BOISSET.

VARIABLE STROKE HYDRAULIC PUMP.

APPLICATION FILED rea. lo. |921.

Patented June 6, 1922.,

. 3 SHEETS-SHEET 3.

. L framers VARIABLE-STROKE HYnRAULrcrotar. 'jj I hydraulic pumps, it being more particularly animprovement on vthe pump disclosed in I' my co-pending application-for Letters Fatg ent filed June 5,1920', Serial No. 386,764,

and itv consists in the constructions, combinations and modeof operation hereinde- Y scribed and claimed.

Qne ofthe foremost objectsioif ythe inve-ntion lis to provide a uniformly driven vari,- able stroke pump of avery simple"construc-k tion, enabling obtaining any motorspeedvr between predetermined limits.

A further Vobject of the Ainvention ist-to 'provide means inthis pump, `for varying the 7 pistonstroke' Without shock or jar, `thereby enabling an easy progression from o ne' speed i t0 4another throughout the rangeof speeds which the pump is capable of producing in the operatively associatedmotor.

A furher object ofl he invention V' is Ite provide -in combination With thepump,a

pressure relief` device or shock absorber, the

specific functiony of which vis to 4make the fluid outlet valves yclose promptly instead oi lagging behind.

Other objects and advantagesvvill appear in the following specification, reference'be `ing had to the accompanying drawings, in

which :V i

Figure 1 is a diagram illustratingtlie lgeneral lrelationship of the improved pump With a vhydraulic transmission system,

Figure Qis a detail, sectional vview of the shock absorber which functions'in connection with the pump to close the iiuid outlet valves; Figure 3 is ajlongitudinal section ofthe i hvdr'aulicpump, corresponding to the positionshovvn in Figure 1, ,i

Figure 4 is a diagram showin how-the adjustable; fulcrum may vary te piston stroke,

Figure. 5 lis a detail section on the line' 5-,5 of vFigure 3,

,Figure iis a cross section taken substantially on the line :6-6 `o-Figure 3,

Figure 7 is a `horizontal' section taken i Specification of Letters Patent. I Paten and labsorber illustrated in FigureQ. f y

In order to show in lvvhat connection thetedilune 'CHARLES LEONv Borssnr, or nnvronnnens, Lofi-ristlimita". Y

Substantially 'onf the une prf er Figure ej f 1 i Figure 8 a detailplan vievv'of` l i 60 improvedhydraulic pump; 1 is used,-atten;` Y

This system may be like that disclosed in my oo -pending applicatlon filed J une 5 ,192 O,=

Serial No. 386,764, orfin my Ignorerecent cofv 'f f tion is 'directed yto Figure 1 ',fvvherein a` 'i hydraulic'transmission vsystem, isillus'trated.

pending, applicationfo'rjLetters Pa-tentlon-" steering apparatus l'or.tractorsjledjFeh `f i0, 1921,- seriai-NO. 444,027. There-ns1 a fluidg reservoir 2- .from the bottom fot which the '1 pipe 3 leadstothe 'inlet chambers Land 5.'

The outlet chambers 6v and 1-fof' thepunipi have" a; pipe y connection 8 discharging y ,the reservoir butk embracing ftheiour-'vvay y valve 9, by means of Whichthe directionfof l i koperation of the hydraulic.motorsjjlOvand 1 1' isn controlled,l Connected to thefvalvefQ at'` i points 9.0? `l fromfthe1 partsfof p ip ei,8, are pipes 12 and 13 leading to the v cylinders le and 15, ofthe shockabsorberinFigure 2l.'

Thev pipes 12 and 13 lhave continuationsfl .'ff

and 17 lto one side vof eachfinotorand" 18j land 19 totheother sides oftliese'motors'- vRelief pipes 20 and,21 communicate bef,

tvveen the cylinders 14 and and This gives a galera @hasta uit: hydraulic system and attention isn'ow more particularly directed-tothe pump" structure shown for example Figure `Inl thecasl'j ing. 1 there is `iournalled the 'eccentiije shaft I 22'Which is also the ,enginef'sliafft' inasmuch r as itk extends o'if'into the engine' IFi.generally t' driven atan'approximately uniform speed, 4 but ythesftrokesfof the pistons 23 in; the ,op-'f Aposed pumpcylinders 2li, are variableso as to 'inturnv'aiy the'speed ofthevhydraulic y designated in Figure 6. Theengine is -motors 10 andliA in a. c cordance `fthe".

volume/of.' fluid delivered thereto.` f

' A plurality of eccentrics 25 arekeyedit i the eccentricshafh the presentin'stance there are shown two s etsof cylinders, land i y consequently only tvvo eccentricsQ The pump" may consist of more than four'cylinders, `the` actual numbery dependin'gon the nature of' vth'eyvorl; iny connection 'vvith which it is Lin-' tended to be used. The eccentricsfare approximately 90o apart. f

to a rockery bar 28 .which made round A throughout its upper part to readily enable sliding of the Jfulcruin'29. rThis lulcrum is made of ashort section of round rod. That is Why it appears circular in the end viewy in Figure 3. A hole is bored into this short section' to accommodate the rocker bar 25%. There are trunnions 30 at each end to provide pivotal mountings for the side parts ci 34 which joins two pistons.

'the radius link 3l..

eccentric is always the same. `When the ulcrum 29 is moved to its lowerinost position c, the stroke ft2 oit the connecting rod 34 1s approximately the saine 'as that oli/the ec centric: Should it be desiredv to diminish vthe output of the pump, the fiilcrum is moved up anywhere betvveen the extremities of position itis intended to occupy, until 'the upper extremity b isfreached,

Now the stroke bVV ot the connecting rod 34 is greatly diminished, but the-stroke oit the eccentric remains the same as bet'orc.

. lt is simply a question olishift-ing the Ll'ulcrum up or down, thereby changingr vthe v stroke ofthe pump according to the changes in leverage in the rocker bar 28. lt may be emphasized that the speed of' the engine and v stroke ot the eccentric remain `the same,

,but the stroke oit' the pump or the pistons therein' is variable and consequently the speed of operation of the motors l0 and ll is variable. Y

' Atv the head ot each piston there is an routletchamber@ which is common to all l. ately above.

olf` the outlet valves (at present two on eachy side) 42. These are seated in the partition 43 by springslta in the caps 45 which siipport and guide the valve stems. A port 46, cast yon the `outside oli the cylinder 241, communicates" with the outlet chamber 6. A port t7l provides communication betweenthe cylinder and the y,valf-,ierchamber immedi- Thereis one of these chambers above both cylinders, and the chambers contain the inlet valves 48, alsoy pressed to their seats by springs L19in caps 50 which additionallyy serve `to-guide1 the valve seats. The con-- struction on each' sidev ot' the pump is the same, and the foregoing` description ot one side vsuttices tor both. ,The pump is double actingfvby virtue of having the cylinders and pistons inl tandem. c

The operationfmay now be *reviewed to advantage, in so" far as` the pump is concerned. lithas already been made clear in ifiisie connection with vFigure' il, that When the yfulcruni 29 is moved down to the point a, the :full stroke of the eccentric @251s imparted to the pistons. Consequently, the

motors l() vand' l] operatey at maximum speed, due to the maximum volume of-lui'd. delivered. i

When the 'fulcruin is'adjusted high there is a diminution in the volume o'flluiddelivered past the outlet vvalves 42,' naturally by reason of the reduced piston strokes, ,and consequently the motors operate that muchv slower. lt only remains to be stated that reversal of the motors is obtained byiturning the valve 9 to ai' position. 90 away from that shown in Figure l, and when the `valve plug is turned into a central position so that the port 5l brings the adjacent parts oit the pipe. 8 into communication, there vis simply av circulation between the' pump and reser voir, and no drivingof the motorsresults;

The shock absorber in Figure 2, ris indispensable in that it is through its instru.- ment'alities the outletvalves'4f2'are closed promptly, thereby l contributing immeasurably to the efficient operation of.c the pump. llach cylinder'l4, 15 has a piston 52 pressed inwardly by a spring v53 adjustable' in tension either by thefmeans 54 or other equivaf lentmeans. .l v

' Below the head of each pistonfthere is the outletto the relief'pipes 20, 21., which f lead to thc pump casing or some other .convenient point. As [fluid v is disclifargedby the pump it enters `one or theotherof the cylinders 14 and 15 either by Way of the pipe 12 or 13, depending on .thev posit/iondol,VV

the valve 9.,` There is therefore a pressure against one oi the pistons 5,2. vButfthis pressure is opposed bythe springs behind, l

Now this spring`r pressure makes itself eyif'v dent on the Huid column in front ot thepiston at that instant when the valvei2-starts` to close on the recession of the pump piston 23, at that time causing' a 'quick and. positive closure oi thevalve and preventing` any .-oil, from getting back into the cylinderl24l, which it might do il there be any lagging in the operation ottheoutlet valve.V

A turtherpurpose of the shock absorber counter pressure."

is to provide a relief 'tor` the hydraulic Jsyspump as lierein described andclaiined, is f that of a generally preferred form, olovviously modifications and changes may be made Withoutdeparting from the spirit of the invention or the scope of the claims.

l. In a. pump, a connecting rod between pistons in two cylinders; a uniformly driven engine shaft With an eccentric and strap, a rocker bar pivoted between the connecting rod and strap, a ulcrum slidable on the bar,

lcomprising a piece with trunnions; a radius link. pivoted to the` piece at the trunnions,

fluid conduits,'ineans in the` outlet conduit producing counter pressure to cause `the outlet `'valve' to Vvclose promptly, including" a.

pump piston With afconnecting' rod, a uni- .and a screw shaft With a swivel yokey having strap connection to the link.` v pump, comprising va cylinder r,with f vai-lved inlet and outlet chambers leadingv to p.

.cylinder with a spring-pressed piston `a'` l rocker bar connection to saidy rod, and a'fulj crum for the rocker Vbar,"with means for f stroke from that of the eccentric. l CHARLES LEON' BOISSE,

raising and lowering it to changey the pump 

